scholarly journals Roof Control Technology of Mining Roadway under the Influence of Advanced Supporting Pressure

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Zhiyuan Jin ◽  
Youlin Xu ◽  
Tao Peng ◽  
Linsheng Gao
Keyword(s):  
Simulation Method ◽  
Industrial Test ◽  
Support Pressure ◽  
Row Spacing ◽  
Hydraulic Support ◽  
Control Plan ◽  
Column Method ◽  
Control Scheme ◽  
Hydraulic Prop ◽  
The One

In order to solve the problem of controlling the roof of the stoping roadway in 1204 fully mechanized face under the influence of advanced support pressure, according to the characteristics of the stoping roadway section, the single hydraulic prop and π-shaped steel beam were selected to verify the shrinkage of the single hydraulic support and establish mechanics. The model calculates that at least 3 single hydraulic props and at least 2 material lanes are required for the transportation lane; through the numerical simulation method, a reasonable roof control plan for the stoping roadway in the advance support section is determined, that is, 0∼ in front of the material lane. The one-beam three-column method is adopted within 30 m, and the row spacing is 0.8 m; the one-beam four-pillar method is adopted within 0–20 m of the working front of the transportation lane; and the one-beam three-pillar method is adopted within 20–30 m, and the row spacing is 0.8 m. On-site industrial test practice proved that the proposed roof control scheme is reasonable, and the roadway section can meet the actual production requirements.

scholarly journals Strata behavior and control strategy of backfilling collaborate with caving fully-mechanized mining

2020 ◽  
Vol 12 (1) ◽  
pp. 703-717
Author(s):  
Yin Wei ◽  
Wang Jiaqi ◽  
Bai Xiaomin ◽  
Sun Wenjie ◽  
Zhou Zheyuan
Keyword(s):  
Numerical Simulation ◽  
Control Strategy ◽  
Three Dimensional ◽  
Simulation Method ◽  
Mine Pressure ◽  
Hydraulic Support ◽  
Transition Area ◽  
Pressure Concentration ◽  
Strata Behavior ◽  
And Control

AbstractThis article analyzes the technical difficulties in full-section backfill mining and briefly introduces the technical principle and advantages of backfilling combined with caving fully mechanized mining (BCCFM). To reveal the strata behavior law of the BCCFM workface, this work establishes a three-dimensional numerical model and designs a simulation method by dynamically updating the modulus parameter of the filling body. By the analysis of numerical simulation, the following conclusions about strata behavior of the BCCFM workface were drawn. (1) The strata behavior of the BCCFM workface shows significant nonsymmetrical characteristics, and the pressure in the caving section is higher than that in the backfilling section. φ has the greatest influence on the backfilling section and the least influence on the caving section. C has a significant influence on the range of abutment pressure in the backfilling section. (2) There exits the transition area with strong mine pressure of the BCCFM workface. φ and C have significant effect on the degree of pressure concentration but little effect on the influence range of strong mine pressure in the transition area. (3) Under different conditions, the influence range of strong mine pressure is all less than 6 m. This article puts forward a control strategy of mine pressure in the transition area, which is appropriately improving the strength of the transition hydraulic support within the influence range (6 m) in the transition area according to the pressure concentration coefficient. The field measurement value of Ji15-31010 workface was consistent with numerical simulation, which verifies the reliability of control strategy of the BCCFM workface.

FAST SPRINGBACK SIMULATION OF BENDING FORMING BASED ON ONE-STEP INVERSE ANALYSIS

2008 ◽  
Vol 22 (31n32) ◽  
pp. 6057-6063
Author(s):  
YI-DONG BAO ◽  
WEN-LIANG CHEN ◽  
HONG WU
Keyword(s):  
Sheet Metal Forming ◽  
Metal Forming ◽  
Inverse Analysis ◽  
Simulation Method ◽  
Spring Back ◽  
Deformation Path ◽  
Bending Process ◽  
One Step ◽  
Implicit Solver ◽  
The One

A simplified one-step inverse analysis of sheet metal forming is a suitable tool to simulate the bending forming since the deformation path of bending forming is an approximately proportion one. A fast spring-back simulation method based on one-step analysis is proposed. First, the one-step inverse analysis is applied to obtain the stress distribution at the final stage of bending. Then, the unloading to get a spring back is simulated by LS-DYNA implicit solver. These processes are applied to the unconstrained cylindrical bending and the truck member rail. The spring-back and member rail widths at the several key sections are compared with experimental ones. It is well demonstrated that the proposed method is an effective way to predict the spring-back by unloading after bending process.

scholarly journals Synergies in coordination: a comprehensive overview of neural, computational, and behavioral approaches

2018 ◽  
Vol 120 (6) ◽  
pp. 2761-2774 ◽  
Author(s):  
Michaela Bruton ◽  
Nicholas O’Dwyer
Keyword(s):  
Motor Control ◽  
Hierarchical Control ◽  
Research Approach ◽  
Comprehensive Overview ◽  
Control Scheme ◽  
The One ◽  
Explanatory Concept ◽  
Different Levels ◽  
And Task

At face value, the term “synergy” provides a unifying concept within a fractured field that encompasses complementary neural, computational, and behavioral approaches. However, the term is not used synonymously by different researchers but has substantially different meanings depending on the research approach. With so many operational definitions for the one term, it becomes difficult to use as either a descriptive or explanatory concept, yet it remains pervasive and apparently indispensable. Here we provide a summary of different approaches that invoke synergies in a descriptive or explanatory context, summarizing progress, not within the one approach, but across the theoretical landscape. Bernstein’s framework of flexible hierarchical control may provide a unifying framework here, since it can incorporate divergent ideas about synergies. In the current motor control literature, synergy may refer to conceptually different processes that could potentially operate in parallel, across different levels within the same hierarchical control scheme. There is evidence for the concurrent existence of synergies with different features, both “hard-wired” and “soft-wired,” and task independent and task dependent. By providing a comprehensive overview of the multifaceted ideas about synergies, our goal is to move away from the compartmentalization and narrow the focus on one level and promote a broader perspective on the control and coordination of movement.

scholarly journals Fully stabilized multi-TW optical waveform synthesizer: Toward gigawatt isolated attosecond pulses

2020 ◽  
Vol 6 (16) ◽  
pp. eaay2802 ◽  
Author(s):  
Bing Xue ◽  
Yuuki Tamaru ◽  
Yuxi Fu ◽  
Hua Yuan ◽  
Pengfei Lan ◽  
...  
Keyword(s):  
Harmonic Spectrum ◽  
Pump Laser ◽  
X Ray ◽  
High Order Harmonic ◽  
Delay Dependence ◽  
Control Scheme ◽  
Active Stabilization ◽  
Waveform Synthesis ◽  
Spectrum Intensity ◽  
The One

A stable 50-mJ three-channel optical waveform synthesizer is demonstrated and used to reproducibly generate a high-order harmonic supercontinuum in the soft x-ray region. This synthesizer is composed of pump pulses from a 10-Hz repetition-rate Ti:sapphire pump laser and signal and idler pulses from an infrared two-stage optical parametric amplifier driven by this pump laser. With full active stabilization of all relative time delays, relative phases, and the carrier-envelope phase, a shot-to-shot stable intense continuum harmonic spectrum is obtained around 60 eV with pulse energy above 0.24 μJ. The peak power of the soft x-ray continuum is evaluated to be beyond 1 GW with a 170-as transform limit duration. We found a characteristic delay dependence of the multicycle waveform synthesizer and established its control scheme. Compared with the one-color case, we experimentally observe an enhancement of the cutoff spectrum intensity by one to two orders of magnitude using three-color waveform synthesis.

An Analysis of Electric Inertia Simulation Method on the Test Platform of Electric Bicycle Brake Force

2014 ◽  
Vol 989-994 ◽  
pp. 3335-3339
Author(s):  
Zhao Xu Yu ◽  
Hong Bin Yu
Keyword(s):  
Simulation Method ◽  
Electrical Simulation ◽  
Mechanical Simulation ◽  
Test Platform ◽  
Electric Bicycle ◽  
Brake Force ◽  
Braking Process ◽  
The One ◽  
The Relationship ◽  
Better Than

This paper analyzes the electric inertia simulation method deeply. By analyzing the brake torgue in the braking process, this paper makes a conclusion about the relationship between the moter’s torgue in the braking process and the simulation of inertia. The test uses the method of combining the mechanical simulation and electrical simulation. In this method, it invites the test platform of electric bicycle brake force, and realizes the inertia simulation. On the test platform, the results showed: by using the electric inertia simulation, the performance of the system is obviously better than the one on the test platform which using flywheel groups. This method improves the degree of automation on the test platform.

scholarly journals A new simulation method for laser speckle imaging to investigate hemodynamics

2019 ◽  
Vol 128 ◽  
pp. 02001
Author(s):  
X Sang ◽  
D Li ◽  
B Chen
Keyword(s):  
Speckle Pattern ◽  
Simulation Method ◽  
Laser Speckle ◽  
Contrast Imaging ◽  
Laser Speckle Imaging ◽  
Speckle Imaging ◽  
Dynamic Speckle ◽  
Speckle Size ◽  
The One

Speckle simulation is a powerful protocol to investigate the properties of speckle and evaluate image processing method. However, only static speckle images can be simulated by available methods without considering time-integrated effect of CCD. A time–integrated dynamic speckle simulation method basedon coherent imaging was developed. Through the new simulation method, the effect of speckle size on LSCI was investigated. The smaller the speckle size is, the higher the spatial resolution become.But the one-dimensional speckle size should exceed two pixels to sample the speckle pattern. The characteristics of existing speckle contrast imaging methods were studied based on spatial statistics, and optimal parameters are given to obtain accurate and less noisy image. In general, the new simulation method for laser speckle imaging is a powerful tool to monitor blood flow in vivo and lay a solid foundation for the study of hemodynamics.

Research on Simulation of Fischer-Tropsch Synthesis Based on Virtual Assembly

2013 ◽  
Vol 336-338 ◽  
pp. 700-707
Author(s):  
Yan Bang Wang ◽  
Yue Feng Su ◽  
Xiao Dong Zhang ◽  
Wen Sheng Deng
Keyword(s):  
Process Simulation ◽  
Chemical Process ◽  
Data Transfer ◽  
Homogeneous Model ◽  
Virtual Assembly ◽  
Simulation Method ◽  
Tropsch Synthesis ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
The One

The scene graph structure of Fischer-Tropsch synthesis (FTS) was constructed. In the meanwhile, the assembly unit model of equipment was designed. The main FTS reactor and its mathematical physical model were described. Platform for chemical process simulation was established, on base of the virtual assembly for FTS. The method of data transfer in common chemical process simulation was proposed. The composition and flow rate of components, as well as the temperature and pressure of the FTS reactor was investigated by the one dimensional quasi homogeneous model. The relative error is less than 3% between the calculation and experiment. The accuracy of the system process simulation is reliable. It is verified that the simulation method of chemical process is feasible on base of the virtual assembly. This work studies a new way for simulation of the FTS, and also provides technologic supports for the simulation of chemical process based on virtual assembly.

Sinusoidal input-based visual control for nonholonomic vehicles

Robotica ◽  
2013 ◽  
Vol 31 (5) ◽  
pp. 811-823 ◽  
Author(s):  
M. Aranda ◽  
G. López-Nicolás ◽  
C. Sagüés
Keyword(s):  
Kinematic Model ◽  
Visual Control ◽  
State Feedback Control ◽  
Control Approach ◽  
Vehicle Trajectories ◽  
Control Scheme ◽  
Sinusoidal Input ◽  
The One ◽  
Nonholonomic Vehicles ◽  
Analytical Expressions

SUMMARYThis paper proposes a new visual control approach based on sinusoidal inputs to be used on a nonholonomic robot. We present several contributions: In our method, developed considering a unicycle kinematic model, sinusoids are used in such a way that the generated vehicle trajectories are feasible, smooth and versatile. Our technique improves previous sinusoidal-based control works in terms of efficiency and flexibility. As further contributions, we present analytical expressions for the evolution of the robot's state, and propose a new state-feedback control law based on these expressions. All the information used in the control scheme is obtained from omnidirectional vision by means of the one-dimensional trifocal tensor. Stability analysis of the proposed approach is presented, and its performance is illustrated through experiments.

Distribution of Cotton in Rectangular Pipeline for Horizontal Foreign Fiber Removed Device

2014 ◽  
Vol 951 ◽  
pp. 113-119
Author(s):  
Gai Li Gao ◽  
Guan Jun Wang ◽  
Peng Chuan Liu
Keyword(s):  
Cross Sections ◽  
Volume Fraction ◽  
Flow Direction ◽  
Simulation Method ◽  
Optimum Length ◽  
Two Phase ◽  
Maximum Volume Fraction ◽  
The Cross ◽  
Motion Characteristics ◽  
The One

A numerical simulation method using the model of the gas-cotton two-phase is used to analyze the distribution of the cotton in the rectangular pipeline for a horizontal foreign fiber removed device. According to the motion characteristics of the cotton, the optimum length of the rectangular pipeline is found and the distribution of the cotton in the pipeline is obtained. The simulation results show that the optimum length is for the cross-section pipeline. At the same time, in the range of the cotton mainly flows in the middle of the pipeline bottom and the maximum volume fraction of the cotton is 4.5%, at the both sides of the pipeline bottom the cotton is less and the average volume fraction of the cotton is 1%, and there is no the cotton in the middle and upper part of the pipeline; in the range of , the cotton increases rapidly in the middle and upper part of the pipeline and the volume fraction is about 2.7% at ; in the range of , the cotton flows steadily and the volume fractions of the cotton are the same in the middle and upper part of the pipeline, about 2.7% but 1.5% in the lower part of the one. In addition, for the level centers of the cross-sections perpendicular to the cotton flow direction, in the unsteady zone the volume fraction curves of the cotton are symmetrical like a saddle, and in the steady zone the cotton is evenly distributed and its volume fraction curves are horizontal lines.

scholarly journals Multi-scale Simulations of Dry Friction Using Network Simulation Method

2016 ◽  
Vol 1 (2) ◽  
pp. 559-580 ◽  
Author(s):  
F. Marín ◽  
F. Alhama ◽  
J. Solano ◽  
P.A. Meroño ◽  
J.F. Sánchez
Keyword(s):  
Initial Conditions ◽  
Network Simulation ◽  
Network Models ◽  
Simulation Method ◽  
Atomic Scale ◽  
Scale Model ◽  
Narrow Scope ◽  
The One ◽  
High Level ◽  
Network Simulation Method

AbstractThe study of everyday phenomena involving friction continues to maintain a high level of difficulty despite its long history. The causes of this problem lie in the different scale of the characteristics of the phenomenon, macroscopic and microscopic. Thus, very different models, valid in a narrow scope which prevents generalization, have been appearing. This survey presents the application of network simulation method to the numerical solution to the study of friction at very different scales. On the one hand, on a microscopic scale an atomic force microscope model has been studied, related to the analysis of soft surfaces at the atomic scale. Furthermore, on a macroscopic scale model related to the analysis of an industrial device, such as a brake mechanism has been studied. After presenting herein is a review of the different formulations of the friction force, the nature of the surfaces involved in the phenomenon, as well as the definition of the problems to be analyzed. The design of network models and the implementation of the initial conditions are explained. The results of the application of network models to selected problems are presented. In order to verify the reliability of the proposed models, their results are compared with the solutions obtained by other numerical methods or experimental results, one from a device developed during the preparation of this report.

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